Ventricular Tachycardia in Structural Heart Disease

Outcomes of ventricular tachycardia ablation in patients with ischemic and non-ischemic cardiomyopathy: A propensity-score matched analysis

INTRODUCTION AND OBJECTIVES

Catheter ablation (CA) is effective in the treatment of ventricular tachycardia (VT). Although some observational data suggest patients with non-ischemic cardiomyopathy (NICM) have less favorable outcomes when compared to those with an ischemic etiology (ICM), direct comparisons are rarely reported. We aimed to compare the outcomes of VT ablation in a propensity-score matched population of ICM or NICM patients.

METHODS

Single-center retrospective study of consecutive patients undergoing VT ablation from 2012 to 2023. A propensity score (PS) was used to match ICM and NICM patients in a 1:1 fashion according to age, sex, left ventricular ejection fraction (LVEF), NYHA class, electrical storm (ES) at presentation, and previous endocardial ablation. The outcomes of interest were VT-free survival and all-cause mortality.

RESULTS

The PS yielded two groups of 71 patients each (mean age 63±10 years, 92% male, mean LVEF 35±10%, 36% with ES at presentation, and 23% with previous ablation), well matched for baseline characteristics. During a median follow-up of 2.3 (interquartile range IQR 1.3-3.8) years, patients with NICM had a significantly lower VT-free survival (53.5% vs. 69.0%, log-rank p=0.037), although there were no differences regarding all-cause mortality (22.5% vs. 16.9%, log-rank p=0.245). Multivariate analysis identified NICM (HR 2.34 [95% CI 1.32-4.14], p=0.004), NYHA class III/IV (HR 2.11 [95% CI 1.11-4.04], p=0.024), and chronic kidney disease (HR 2.23 [95% CI 1.25-3.96], p=0.006), as independent predictors of VT recurrence.

CONCLUSION

Non-ischemic cardiomyopathy patients were at increased risk of VT recurrence after ablation, although long-term mortality did not differ.

Catheter Ablation of Ventricular Tachycardia in Ischemic Heart Disease: What Is Known and New Perspectives

PURPOSE OF THE REVIEW

This review aims to evaluate current evidence regarding ventricular tachycardia ablation in patients with ischemic heart disease and explore novel approaches currently developing to improve procedural and long-term outcomes.

RECENT FINDINGS

Recently published trials (PARTITA, PAUSE-SCD, and SURVIVE-VT) have demonstrated the prognostic benefit of prophylactic ventricular tachycardia ablation compared to current clinical practice. Advanced cardiac imaging provides a valuable pre-procedural evaluation of the arrhythmogenic substrate, identifying ablation targets non-invasively. Advanced cardiac mapping techniques allow to better characterize arrhythmogenic substrate during ablation procedure. Emerging technologies like pulsed field ablation and ultra-low temperature cryoablation show promise in ventricular tachycardia ablation. Advancements in mapping techniques, ablation technologies, and pre-procedural cardiac imaging offer promise for improving ventricular tachycardia ablation outcomes in ischemic heart disease.

Radiation therapy for ventricular arrhythmias

Ventricular arrhythmias (VA) can be life-threatening arrhythmias that result in significant morbidity and mortality. Catheter ablation (CA) is an invasive treatment modality that can be effective in the treatment of VA where medications fail. Recurrence occurs commonly following CA due to an inability to deliver lesions of adequate depth to cauterise the electrical circuits that drive VA or reach areas of scar responsible for VA. Stereotactic body radiotherapy is a non-invasive treatment modality that allows volumetric delivery of energy to treat circuits that cannot be reached by CA. It overcomes the weaknesses of CA and has been successfully utilised in small clinical trials to treat refractory VA. This article summarises the current evidence for this novel treatment modality and the steps that will be required to bring it to the forefront of VA treatment.

Ryanodine receptor inhibition with acute dantrolene treatment reduces arrhythmia susceptibility in human hearts

Ryanodine receptor 2 (RyR2) hyperactivity is observed in structural heart diseases that are a result of ischemia or heart failure. It causes abnormal calcium handling and calcium leaks that cause metabolic, electrical, and mechanical dysfunction, which can trigger arrhythmias. Here, we tested the antiarrhythmic potential of dantrolene (RyR inhibitor) in human hearts. Human hearts not used in transplantation were obtained, and right ventricular outflow tract (RVOT) wedges and left ventricular (LV) slices were prepared. Pseudo-ECGs were recorded to determine premature ventricular contraction (PVC) incidences. Optical mapping was performed to determine arrhythmogenic substrates. After baseline optical recordings, tissues were treated with 1) isoproterenol (250 nM), 2) caffeine (200 mM), and 3) dantrolene (2 or 10 mM). Optical recordings were obtained after each treatment. Isoproterenol and caffeine treatment increased PVC incidence, whereas dantrolene reduced the PVC burden. Isoproterenol shortened action potential duration (APD) in the RV, RVOT, and LV regions and shortened calcium transient duration (CaTD) in the LV. Caffeine further shortened APD in the RV, did not modulate APD in the RVOT, and prolonged APD in the LV. In addition, in the LV, CaTD prolongation was also observed. More importantly, adding dantrolene did not alter APD in the RV or RVOT regions but produced a trend toward APD prolongation and significant CaTD prolongation in the LV, restoring these parameters to baseline values. In conclusions, dantrolene treatment suppresses triggers and reverses arrhythmogenic substrates in the human heart and could be a novel antiarrhythmic therapy in patients with structural heart disease.NEW & NOTEWORTHY Ryanodine receptor 2 hyperactivity is observed in structural heart diseases caused by ischemia or heart failure. It causes abnormal calcium leaks, which can trigger arrhythmias. To prevent arrhythmias, we applied dantrolene in human hearts ex vivo. Isoproterenol and caffeine treatment increased PVC incidence, whereas dantrolene reduced the PVC burden. Dantrolene treatment suppresses triggers and reverses arrhythmogenic substrates and could be a novel antiarrhythmic therapy in patients with structural heart disease.

Wild-type transthyretin amyloid cardiomyopathy: expect the unexpected-a case report

Background

General interest and incidence are increasing in wild-type transthyretin amyloidosis (ATTRwt) in recent time. As patient population increases, further knowledge of the management of the frequently encountered interacting cardiac comorbidities is requested to improve treatment of ATTRwt patients.

Case summary

A 73-year-old male ATTRwt patient presented to the outpatient clinic (Day 0) with dyspnoea, leg swelling, and palpitations. At diagnosis, 3 years prior to presentation, he exhibited only minor signs of ATTRwt. At Day 0, clinical examination revealed atrial fibrillation and mild peripheral oedema. Anticoagulant and symptomatic treatment with beta-blocker and diuretics was initiated, and the patient was planned for sub-acute direct cardioversion, and the patient was discharged with a Holter monitor to outpatient care. At Day 7, analysis of the monitoring demonstrated spontaneous conversion to sinus rhythm and, unexpectedly, episodes of high-rate self-remittent sustained monomorphic ventricular tachycardia (VT) and frequent ventricular ectopic beats. At Day 8, a sub-acute coronary angiography was performed which revealed a significant proximal left anterior descending artery stenosis which was treated with percutaneous coronary intervention (PCI) and subsequently an internal defibrillator was implanted. Following visits at 1- and 3-month post-PCI at the outpatient clinic revealed no VT and suppression of ventricular ectopic beats.

Discussion

The case illustrates some of the frequently encountered cardiac comorbidities (e.g. atrial fibrillation, ventricular arrhythmia, and ischaemic heart disease) associated with ATTRwt. A high level of suspicion is warranted to identify treatable cardiac conditions [atrial fibrillation, atrioventricular (AV) block, and ischaemic heart disease] and to uncover potentially fatal cardiac conditions in patients with ATTRwt.

Fighting Cardiac Thromboembolism during Transcatheter Procedures: An Update on the Use of Cerebral Protection Devices in Cath Labs and EP Labs

Intraprocedural stroke is a well-documented and feared potential risk of cardiovascular transcatheter procedures (TPs). Moreover, subclinical neurological events or covert central nervous system infarctions are concerns related to the development of dementia, future stroke, cognitive decline, and increased risk of mortality. Cerebral protection devices (CPDs) were developed to mitigate the risk of cardioembolic embolism during TPs. They are mechanical barriers designed to cover the ostium of the supra-aortic branches in the aortic arch, but newer devices are able to protect the descending aorta. CPDs have been mainly designed and tested to provide cerebral protection during transcatheter aortic valve replacement (TAVR), but their use in both Catheterization and Electrophysiology laboratories is rapidly increasing. CPDs have allowed us to perform procedures that were previously contraindicated due to high thromboembolic risk, such as in cases of intracardiac thrombosis identified at preprocedural assessment. However, several concerns related to their employment have to be defined. The selection of patients at high risk of thromboembolism is still a subjective choice of each center. The aim of this review is to update the evidence on the use of CPDs in either Cath labs or EP labs, providing an overview of their structural characteristics. Future perspectives focusing on their possible future employment are also discussed.

Treatment of Arrhythmias During Pregnancy

Cardiac disease is the most common cause of maternal mortality in developed nations. Cardiac arrhythmias are frequent among patients with structural heart disease and may require immediate treatment to prevent hemodynamic instability leading to acute maternal and fetal decompensation. Antiarrhythmic therapy during pregnancy should follow the same principles recommended for nonpregnant individuals. Although multidisciplinary management is recommended, obstetricians, and maternal-fetal medicine specialists may sometimes need to emergently recognize and treat rhythm anomalies before support services become available.

Prognostic Value of Cardiac Troponin I in Patients with Ventricular Tachyarrhythmias

Besides the diagnostic role in acute myocardial infarction, cardiac troponin I levels (cTNI) may be increased in various other clinical conditions, including heart failure, valvular heart disease and sepsis. However, limited data are available regarding the prognostic role of cTNI in the setting of ventricular tachyarrhythmias. Therefore, the present study sought to assess the prognostic impact of cTNI in patients with ventricular tachyarrhythmias (i.e., ventricular tachycardia (VT) and fibrillation (VF)) on admission. A large retrospective registry was used, including all consecutive patients presenting with ventricular tachyarrhythmias from 2002 to 2015. The prognostic impact of elevated cTNI levels was investigated for 30-day all-cause mortality (i.e., primary endpoint) using Kaplan–Meier, receiver operating characteristic (ROC), multivariable Cox regression analyses and propensity score matching. From a total of 1104 patients with ventricular tachyarrhythmias and available cTNI levels on admission, 46% were admitted with VT and 54% with VF. At 30 days, high cTNI was associated with the primary endpoint (40% vs. 22%; log rank p = 0.001; HR = 2.004; 95% CI 1.603–2.505; p = 0.001), which was still evident after multivariable adjustment and propensity score matching (30% vs. 18%; log rank p = 0.003; HR = 1.729; 95% CI 1.184–2.525; p = 0.005). Significant discrimination of the primary endpoint was especially evident in VT patients (area under the curve (AUC) 0.734; 95% CI 0.645–0.823; p = 0.001). In contrast, secondary endpoints, including all-cause mortality at 30 months and a composite arrhythmic endpoint, were not affected by cTNI levels. The risk of cardiac rehospitalization was lower in patients with high cTNI, which was no longer observed after propensity score matching. In conclusion, high cTNI levels were associated with increased risk of all-cause mortality at 30 days in patients presenting with ventricular tachyarrhythmias.

Progression of infarct-mediated arrhythmogenesis in a rodent model of heart failure

Heart failure (HF) post-myocardial infarction (MI) presents with increased vulnerability to monomorphic ventricular tachycardia (mmVT). To appropriately evaluate new therapies for infarct-mediated reentrant arrhythmia in the preclinical setting, chronologic characterization of the preclinical animal model pathophysiology is critical. This study aimed to evaluate the rigor and reproducibility of mmVT incidence in a rodent model of HF. We hypothesize a progressive increase in the incidence of mmVT as the duration of HF increases. Adult male Sprague-Dawley rats underwent permanent left coronary artery ligation or SHAM surgery and were maintained for either 6 or 10 wk. At end point, SHAM and HF rats underwent echocardiographic and invasive hemodynamic evaluation. Finally, rats underwent electrophysiologic (EP) assessment to assess susceptibility to mmVT and define ventricular effective refractory period (ERP). In 6-wk HF rats (n = 20), left ventricular (LV) ejection fraction (EF) decreased (P < 0.05) and LV end-diastolic pressure (EDP) increased (P < 0.05) compared with SHAM (n = 10). Ten-week HF (n = 12) revealed maintenance of LVEF and LVEDP (P > 0.05), (P > 0.05). Electrophysiology studies revealed an increase in incidence of mmVT between SHAM and 6-wk HF (P = 0.0016) and ERP prolongation (P = 0.0186). The incidence of mmVT and ventricular ERP did not differ between 6- and 10-wk HF (P = 1.0000), (P = 0.9831). Findings from this rodent model of HF suggest that once the ischemia-mediated infarct stabilizes, proarrhythmic deterioration ceases. Within the 6- and 10-wk period post-MI, no echocardiographic, invasive hemodynamic, or electrophysiologic changes were observed, suggesting stable HF. This is the necessary context for the evaluation of experimental therapies in rodent HF.NEW & NOTEWORTHY Rodent model of ischemic cardiomyopathy exhibits a plateau of inducible monomorphic ventricular tachycardia incidence between 6 and 10 wk postinfarction.

Clinical spectrum and long-term course of sustained ventricular tachycardia in pediatric patients: 10 years of experience

OBJECTIVE

Pediatric ventricular tachycardias (VTs) have heterogeneous etiology and different clinical features. This study aimed to evaluate the clinical spectrum and long-term course of pediatric sustained VTs.

METHODS

Patients diagnosed as having sustained VT between 2010 and 2020 were evaluated retrospectively.

RESULTS

A total of 129 patients with VT were evaluated; 74 patients were male, and the median age was 12.5 years (0.25-18 years). Patients were grouped as having idiopathic VT (IVT) [n=85 (65.9%)], cardiomyopathy-associated VT (CMP-VT) [n=24 (18.6%)], catecholaminergic polymorphic VT [n=17 (13.2%)], and myocarditis-associated VT [n=3, (2.3%)]. Palpitations (n=61) and syncope (n=24) were the most common symptoms. VT originated from the right ventricle in 53.6% of the patients. Half of the patients underwent electrophysiological study, 64 patients received radiofrequency ablation therapy, and 29 patients had implantable cardiac defibrillators. During the follow-up, 70.4% of all patients had complete resolution, whereas 19 patients had a partial resolution and 23 patients (19.5%) had stable disease. Monomorphic VTs and VTs with left bundle bunch block were more thriving controlled (p=0.02 vs. p=0.04). In terms of long-term results, no statistical difference was found among the VT groups (p=0.39). Deaths were observed only in IVT (n=1) and CMP-VT (n=8) groups (p<0.001), and the overall mortality rate of pediatric sustained VT was observed at 6.9% in this study.

CONCLUSION

VTs, which can cause sudden cardiac arrest, are potentially life-threatening arrhythmias. Identifying the heterogeneity of this VT and its peculiar characteristics would facilitate appropriate diagnosis and therapy.